Technically this is called the JohnNXT 5, though even Steve Guttenberg's minority friend won't be fooled that this isn't the real Johnny Five. LEGO fan Daniele Benedettelli built this entire thing out of LEGO Mindstorm NXT parts, which if our calculations are correct, means this probably costs as much as an actual robot to make.

If you want to build your own (who wouldn't), check out the materials list to get started. – Jason Chen